EA Legislation
Ontario Environmental Assessment Act (OEAA)
An Environmental Assessment, or EA, is a decision-making process used to promote
good environmental planning by assessing the potential effects of certain activities on
the environment. In Ontario, this process is defined and finds its authority in the
Ontario Environmental Assessment Act (OEAA), RSO 1990. The purpose of the OEAA
is to provide for the:
• protection;
• conservation; and,
• wise management of Ontario's environment.

To achieve this, the OEAA ensures that environmental problems or opportunities are considered and their effects are planned for, before development or building takes place.
The OEAA requires that MTO, complete an Individual EA that complies with the requirements of the Act by:
• accurately describing the undertaking;
• considering 'alternatives to the undertaking';
• considering alternative methods for the undertaking;
• consulting with the public;
• detailing impacts and mitigation; and,
• documenting all of the above for public review.
Ontario Environmental Assessment Act
Canadian Environmental Assessment Act (CEAA)
In addition to the Ontario Environmental Assessment Act (OEAA), the Canadian Environmental Assessment Act (CEAA) subjects some projects to a federal EA process.
The federal process is conducted either as a Screening or a Comprehensive Study.
A Screening under the CEAA must include:
• description of the project;
• description of the existing environment;
• the environmental effects of the project including cumulative effects, and the
effects of possible accidents or malfunctions;
• the significance of environmental effects;
• technically and economically feasible measures that would reduce or eliminate
any significant adverse environmental effects of the project;
• comments from the public that are received in accordance with the Act and
the regulations; and,
• any other matters relevant to the screening that the responsible authority
may require to be considered.
The majority of federal projects are assessed through a screening; however, some projects require a comprehensive study. These projects are described in the Comprehensive Study List Regulations. (please refer to website below)
Early on in the comprehensive study, the Minister of the Environment has to decide whether the project should continue to be assessed as a comprehensive study, or whether it should be referred to a mediator or review panel. If the Minister decides the project should continue as a comprehensive study, the project can no longer be referred to a mediator or review panel.
For more information, please go to the Canadian Environmental Assessment Agency Web site at www.ceaa.gc.ca
The Canadian Environmental Assessment Agency has the responsibility for administering the Canadian Environmental Assessment Act and;
• promotes environmental assessments as a planning tool to protect and
sustain a healthy environment;
• promotes co-ordination among federal agencies and with provincial agencies;
• through workshops and training programs, creates an awareness of the
Canadian Environmental Assessment Act and how it applies; and,
• acts as a resource to federal authorities with responsibilities under CEAA, to
proponents and to the public in interpreting CEAA.
Canadian Environmental Assessment Act
Basics of Federal Environmental Assessment and Screening Process